Nagaraja Naik

Publications (2)5.3 Total impact

• Article: Synthesis, antioxidant and antimicrobial activity of novel vanillin derived piperidin-4-one oxime esters: Preponderant role of the phenyl ester substituents on the piperidin-4-one oxime core.

  Salakatte Thammaiah Harini, Honnaiah Vijay Kumar, Javarappa Rangaswamy, Nagaraja Naik
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  ABSTRACT: The study has been achieved the efficient synthesis of vanillin derived piperidin-4-one oxime esters (5a-m) via four step reaction involved Mannich reaction of vanillin, acetone and ammonium acetate to obtain 2,6-bis(4-hydroxy-3-methoxyphenyl)-piperidin-4-one 2 followed by N-methylation and oximation. Further, to enhance the biological activity of vanillin derived piperidin-4-one oxime core, esterification of 4 with substituted benzoyl chlorides in the presence of strong organic base t-BuOK accomplished a series of vanillin derived piperidin-4-one oxime esters (5a-m). The synthesized analogues are screened for their antioxidant and antimicrobial studies and the preponderant effect of the phenyl ester substituents on the biological activity of piperidin-4-one oxime core was demonstrated. Among the tested compounds, 5i and 5j are emerged as outperformed antioxidants than standard Butylated hydroxy anisole (BHA) whereas, compounds 5b and 5d manifested potent antibacterial and antifungal activity than standard streptomycin and fluconazole respectively.
  Bioorganic & medicinal chemistry letters 10/2012; · 2.65 Impact Factor
• Article: Synthesis of benzofuran based 1,3,5-substituted pyrazole derivatives: as a new class of potent antioxidants and antimicrobials--a novel accost to amend biocompatibility.

  Javarappa Rangaswamy, Honnaiah Vijay Kumar, Salakatte Thammaiah Harini, Nagaraja Naik
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  ABSTRACT: In search for a new antioxidant and antimicrobial agent with improved potency, we synthesized a series of benzofuran based 1,3,5-substituted pyrazole analogues (5a-l) in five step reaction. Initially, o-alkyl derivative of salicyaldehyde readily furnish corresponding 2-acetyl benzofuran 2 in good yield, on treatment with 1,8-diaza bicyclo[5.4.0]undec-7-ene (DBU) in the presence of molecular sieves. Further, aldol condensation with vanillin, Claisen-Schmidt condensation reaction with hydrazine hydrate followed by coupling of substituted anilines afforded target compounds. The structures of newly synthesized compounds were confirmed by IR, (1)H NMR, (13)C NMR, mass, elemental analysis and further screened for their antioxidant and antimicrobial activities. Among the tested compounds 5d and 5f exhibited good antioxidant property with 50% inhibitory concentration higher than that of reference while compounds 5h and 5l exhibited good antimicrobial activity at concentration 1.0 and 0.5 mg/mL compared with standard, streptomycin and fluconazole respectively.
  Bioorganic & medicinal chemistry letters 05/2012; 22(14):4773-7. · 2.65 Impact Factor